Scientific Review of Human T-cell Lymphotropic Virus Type 1 (HTLV–1)

Primary Uses or Exposures: HTLV-1 is a retrovirus that people are exposed to through contact with contaminated cells or biological tissues, such as breastfeeding, sharing of needles or syringes with infected individuals, or unprotected sexual activity. It is not transmitted by casual contact. Approximately 90,000 people in the United States are infected with HTLV-1.